This invention relates to clutch calibration and in particular to the determination of the so-called "Kiss-point" of a clutch when the clutch just begins to make frictional contact during its engagement.
It is known to provide clutch control systems in which the clutch is engaged and disengaged by an hydraulic actuator (or some other actuator such as an electric motor) under the control of an electronic control means which, for example, engages the clutch for vehicle start-up when the accelerator is depressed, disengages the clutch when the vehicle comes to a halt, and which disengages the clutch during ratio changes in an associated transmission when a gear selector lever is moved by the operator. Examples of such clutch control systems are disclosed in, for example, European patents 0038113, 0043660, 0059035, 0101220 and 0566595.
In order to ensure the continued accurate operation of such clutch control systems it is necessary for the electronic control means to know accurately the position of the clutch kiss-point. This therefore presents a problem since the kiss-point changes as the clutch and the associated actuating mechanism wears.